Fuel Cost Calculator
Estimate the gas or petrol cost of any trip from distance, fuel economy, and price. Works with US and UK MPG, litres per 100km, and km per litre.
Guide
How it works
This calculator works out how much fuel a journey uses and what it costs. It converts everything to a common metric base, so you can mix units freely: enter distance in miles or kilometres, fuel economy as MPG, litres per 100km, or km per litre, and price per gallon or per litre.
How it works: Fuel used = distance divided by fuel economy. Trip cost = fuel used multiplied by the price of that fuel. The trips field multiplies the result, so you can turn a one-way figure into a round trip, a weekly commute, or a monthly total.
Note that US and UK gallons are different sizes (a UK gallon is about 20% larger), which is why MPG figures and pump prices do not compare directly between the two. Picking the right unit matters.
What is the difference between US MPG and UK MPG?expand_more
A UK gallon (4.546 litres) is larger than a US gallon (3.785 litres), so the same car shows a higher MPG figure in the UK. Always match the MPG type to where the figure came from, or the cost will be off by about 20%.
How do I convert L/100km to MPG?expand_more
They move in opposite directions: a lower L/100km means better economy, while a higher MPG means better economy. This calculator handles the conversion for you, so just enter your number in whichever unit your car or country uses.
How can I estimate my monthly fuel cost?expand_more
Enter your typical one-way commute distance and set the trips field to the number of one-way journeys you make in a month (for example 2 trips per work day times about 22 work days is 44). The total cost line then shows the monthly figure.
Why is my real fuel cost higher than the estimate?expand_more
Stated fuel economy is measured under ideal conditions. City driving, heavy loads, air conditioning, cold weather, and aggressive acceleration all lower real-world economy, so treat the result as a planning estimate rather than an exact figure.
Next steps